mathschallenge.net

Problem

If you multiply together the digits of the number 42, 4 2 = 8, but if you add the digits together, 4 + 2 = 6. For the number 31, the product of the digits, 3 1 = 3 and the sum of the digits, 3 + 1 = 4.

Can you find a two-digit number for which the product of its digits is the same as the sum of its digits?